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fokiten
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Postby fokiten » Mon Jan 30, 2006 5:39 pm

Regards,

First off thanks for your efforts.

One item in your last drawing looks a bit self defeating...

Item H would seem to be a straight-line connection from the end of the bar directly to the aft end of the wing tip; so isolating and the rest of the set up.

What's up with that?

Am I seeing it wrong?

Thanks
fo

Fer1000er
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Postby Fer1000er » Mon Jan 30, 2006 5:40 pm

tplowe56, thanks for the website...

do you know if we can buy there also the bridle replacement rope? and which is the kind of rope and diameter we should use...

Thanks

Fernando

P.D. I was thinking to replace the pulleys rope in the Bar...any idea which kind of rope could be have more resistant agains wearing..

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ScottM
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Postby ScottM » Mon Jan 30, 2006 5:41 pm

Kiterider2000, great work!

I haven't got a Crossbow 12 yet, but hope to soon and like you I have been thinking of when Cabrinha come out with a lower pressure 07 bridle setup can the 06 be upgraded as such.

Anyway it all looks to make sense to me and perhaps I'll try it out soon after I see what all this bar pressure stuff is about. Keep us posted if you notice any side effects because of the change.

Scott

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jatkinson
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Postby jatkinson » Mon Jan 30, 2006 5:44 pm

fokiten wrote:Regards,

First off thanks for your efforts.

One item in your last drawing looks a bit self defeating...

Item H would seem to be a straight-line connection from the end of the bar directly to the aft end of the wing tip; so isolating and the rest of the set up.

What's up with that?

Am I seeing it wrong?

Thanks
fo
That is how it is set up stock from Cab (see drawing #1). All he has done is add a pulley on the front tow point. He has not proposed any changes to how the backlines connect

JJ

fokiten
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Postby fokiten » Mon Jan 30, 2006 5:51 pm

So?

No change= no change?

I certainly do not wish to be seen as negative here, it's that I see no mechanical advantage in the "change".

what the f*** do I know?

carry-on,, if it works, it works
fo

Ps. hold everything,,,Is there now a new frontline pigtail/connection above the bonus pulley?

If so what's the old connection for?

the more I look the confuseder I get...

I'll just shut up,,,and see how it plays out,,,

Never-mind..

carry-on
fo

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tplowe56
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Postby tplowe56 » Mon Jan 30, 2006 6:11 pm

Here is the line I use for kites:

http://www.layline.com/prodinfo.asp?number=S1218

It is 1/8" Dyneema. It is the same line that many kite companies use on their bars. Comes in Grey,Red,Green. Hollow core, super easy to splice, to make a nice loop if you need it. Last time I bought it Layline sold it in a 7/64" size which is 100th's of an inch smaller, 7/64's doesn't seem to be available anywhere. I bought 150' of it in 2004 @ .19 a foot, now it's .41. Yikes!

FYI: The bigger stuff is good for CL line.

As for replacing the Cabbie line with an exact match, I have never seen that type of line for sale, and it looks like it would be much harder to work with.
Last edited by tplowe56 on Mon Jan 30, 2006 6:56 pm, edited 1 time in total.

tukyank
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Postby tukyank » Mon Jan 30, 2006 6:51 pm

Great Work!

Has anyone from Cabrinha taken "offical" notice yet?
I suck when it comes to tying knots and fiddling with bridles - I would much prefer to wait for a retro fit Bridle....Hey MFG's - opportunity to make a few $$.

I'm hoping that this improvement lowers the Bar pressure enough so that the stock Stopper Ball will hold...reliably!!!

I look forward to hearing some more postive test results!

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JS
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Postby JS » Mon Jan 30, 2006 8:47 pm

thekiterider2000 wrote:CROSSBOW BAR PRESSURE FIX
JJ Atkinson drew my attention to this development. I am posting my reply to him, because it relates to this issue:

Hi JJ,

Hadn't seen this, but it doesn't surprise me. I think the most obvious area for bow-kite improvement is in bridle geometry. I expect that the next generation Crossbow will be a leap forward, and I hope Cabrinha offers a retro-kit to upgrade the current kites.

In principle, fixed bridles (no pulleys) compromise the bows sheeting advantage because they effectively put the tow points down below the kite, not that different from the low tow points of C-kites. It makes sense that a series of pulleys would solve this. I'd also like to see really high pressure leading edges (tougher material) to make a more rigid structure that wouldn't need as much bridling, if any, because this would be an elegant way to clean up this problem.

I don't know if I mentioned it or not, but I think I may have a solution to the inversion problem, too. From a main bridle junction on each side of the kite, you could run a fairly slack line to the trailing end of a strut on each side of the kite. The length of these lines should be such that they become taught just before the kite reaches zero aoa (luffing head to wind), so the kite wouldn't be prone to inverting (airborne or on the water).

Regarding powerlock, the more I think about it the more I hate to compromise the deadman depower effect of bowkites, because it is one of the greatest safety advances in kiteboarding, which is an otherwise statistically very dangerous sport (too dangerous, really). I actually don't mind the pressure so much because I use kiting as an intense physical workout, (like maximizing resistance in the gym).

HOWEVER, my biggest issue with the lack of powerlock relates to one-handed riding and jumping, which I find really difficult on the Crossbow. So, I am starting to come around to accepting a concept that I have historically shied away from, and that is a lever, sort of like a motorcycle brake, on each side of the bar. As long as you squeeze it against the bar, even on one side only, you'd be locked in, but if you release it a bit or let go, you could sheet out.

The obvious downside of this arrangement is moving parts, but with a clean design it might not be much of a problem. It would be so simple. Each bar could have a single pivot, and an L-shaped end that sticks into the hole in the bar. When you tighten, the L'shaped end would bind against the line through the bar.

Maybe I'll post this to the forum, too.

Cheers,
James

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4T
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Postby 4T » Mon Jan 30, 2006 11:02 pm

they've got a 9m Switchblade hanging from the roof in our local shop and i'm sure it has that exact same configuration with the additional pulley as a standard configuration.

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4T
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Postby 4T » Mon Jan 30, 2006 11:14 pm

hi james,

i have been thinking about a lever activated powerlock too.
but i don't think you need to make it complicated by placing the locking mechanism inside the hole of the bar.
if you use a configuration like a very shallow V, where two levers [~80mm long] either side of the centre are positioned on the bottom of the bar.
the two lever halves are pivoting where they are connected to the bar and they are jamming the rope between the two interlocking levers when they are closed towards the bar.

you could activate them with your thumb grip and they always would release the rope when you let go of the bar and it slides up.
you could make the quite easily from a half circular cross section with a piece of foam for a spring like release.


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